In the related art, a component mounting device is known that mounts a sucked component that is sucked by a suction nozzle on a board and determines the presence or absence of a suction defect of the sucked component such that it is possible to correctly mount the sucked component on the board. For example, the component mounting device of PTL 1 acquires a side image by imaging the suction nozzle from a side at a timing immediately before mounting, calculates a distance from a leading end of the suction nozzle to a lower end of the sucked component based on the side image, and determines presence or absence of so-called vertical suction that the sucked component is inclined without being able to correctly suck a component upper surface by comparing the calculated distance to a reference value.